Submillimeter-Wave Metrology: Enhancement in Measurement Accuracy and Precision

The development of terahertz (THz) frequency technology and THz integrated circuits demand more efficient and effective methods for THz measurement. Consequently, the study of THz metrology has seen rapid progress recently. In this work, two methods of using micromachined components to improve the accuracy and precision of submillimeter-wave measurement are presented. The first method focuses on improving the repeatability and reliability of terahertz probing. The principle of this method is using symmetrical integrated strain sensor pair to monitor and control the contact condition of terahertz on-wafer probe. This method improves the repeatability of terahertz probing and enables accurate contact force measurement without modification to the standard probe station. Repeatable RF measurements can be achieved by aligning the probe tips angularly and controlling the contact force using the integrated strain sensors. Taking advantage of this technique, measurement uncertainty of THz probing can be characterized. In addition, the recommended probe station specifications and procedure for THz probing without any integrated strain sensor are provided. The second method focuses on improving the accuracy of calibration by improving the quality of calibration standards (quarter-wave calibration shims). Microfabricated calibration shims for the WR-2.2 band were fabricated and tested. The corner radii effect can be greatly reduced, which enables the fabrication of geometrically complex waveguide components, such as waveguide twist.